1. Field of the Invention
This invention relates to a light control element using an electro-optical substance.
2. Description of the Prior Art
When a light control element using an electro-optical substance, such as a double-refractive crystal, a liquid crystal, a suspension containing dipole molecules having a light absorbing property, a ferroelectric ceramic or an electrochromic layer, is placed in the light path of an optical system, it is generally desired that scattering and/or diffraction and undesirable reflection and/or refraction of light be avoided as far as possible. Thus, in the operative area over which the passage of light is to be controlled, the transparent electrodes, the insulation coating and the layer of electro-optical substance should preferably be formed simply as layered, parallel, thin films, for example supported on a substrate. However, such thin films are not always formed uniformly, because of manufacturing variations. The method of manufacture employed may be any of several, including, for example, evaporation, sputtering, enveloping of liquid, plating and photoetching, and the thin films are only rarely sufficiently free of non-uniformity to be fully utilized in numerous optical applications. This presents a particularly serious problem in instances in which the control area is relatively large, as is the case when the electro-optical light control element is to be utilized in such applications as sun glasses, photographic filters, the picture planes of cameras, or the focal planes of aperture portions of optical systems.